Overexpression of α-synuclein in animal models of PD induces the formation of small oligomers, microaggregates, and filaments at synapses, following a similar pathologic cascade that occurs in other neuronal compartments (Scott et al., 2010; Volpicelli-Daley et al., 2011; Spinelli et al., 2014). The gene discussed is SNCA; the disease is Parkinson disease.